I've got a large or LT, can't quite remember that I'm tempted to part with. I'm usually a MT in rip curls but the bigger size fitted me better in the Patagonia. Have you tried one on yet, could be the same for you. Anyway, it's only a few months old, used a handful of times, if it didn't have some wax on chest and knee would still be like new.
Let me know if you could be keen, although I'm not home to sort anything out for 10 days or so.